A cave may not be the best place to live, but
it's ready-made and cheap. This is the estate agent's equivalent
of an old-style monograde oil. Or you could get Hengist Pod to fit
a window and a door; this is moving up to a cheap 'n' cheerful mineral
20W/50. But an architect-designed 'machine for living in', built
up brick by brick, is an allegory of a high performance synthetic
oil.
It is impossible to make a good 5W/40, or even 10W/40, using only
mineral oil. The base oil is so thin, it just evaporates away at
the high temperatures found in a powerful engine that is being used
seriously. Although there are chemical compounds in there to prevent
oil breakdown by oxygen in the atmosphere (oxidation) they cannot
adequately protect vulnerable mineral oil at the 130º C plus
sump temperatures found in hard worked turbocharged or re-mapped
engines.
Synthetics are the answer. They are built up from simple chemical
units, brick by brick so to speak; to make an architect-designed
oil with properties to suit the modern engine.
But sometimes, if you look behind the façade, there is a
murky old cave at the back! This is because the marketing men have
been meddling.
